The present invention relates to hematology parameters measurement apparatus in which particle counting is performed and registers store results, and more particularly to such an apparatus in which hematology parameters are both measured and calculated.
The context contemplated for the present invention is the type of hematology parameter measuring apparatus in which a highly diluted blood sample is passed through an aperture in a conductivity sensor which produces a number of output pulses indicative of the number of blood cells in the blood sample. The apparatus further includes means for measuring hemoglobin by colorimetric analysis. An example of such an apparatus is disclosed in U.S. Pat. No. 3,921,066 to Henry R. Angle and James W. Hennessy, issued Nov. 18, 1975. This patent is now assigned to the assignee herein, and the disclosure thereof is incorporated herein by reference. Parameters measured by such apparatus include red blood count (RBC), white blood cells (WBC), and hemoglobin (HGB). It is also desirable to obtain values of further parameters such as hematocrit (HCT), which is the percentage by volume of a blood sample consistng of red blood cells. Hematocrit may be measured by totalizing the volume of red blood cells in a sample and multiplying or dividing by a scaling factor to account for blood sample volume. While this involves a calculation, for purposes of the present description, hematocrit is referred to as a measured parameter. An example of hematocrit measurement apparatus is disclosed in commonly assigned U.S. patent application Ser. No. 725,268 now U.S. Pat. No. 4,068,169 filed Sept. 21, 1976 by Henry R. Angel and Bernard O. Bachenheimer, the disclosure of which is incorporated herein by reference. It is also desirable to obtain indications of what are herein referred to as calculated values such as mean corpuscular volume (MCV). This is referred to as a calculated value herein because MCV may be calculated as hematocrit divided by RBC. An example of a circuit useful in the present type of hematology parameter measuring apparatus for providing a calculated value indicative of MCV is disclosed in U.S. patent application Ser. No. 723,805 now U.S. Pat. No. 4,063,309 filed Sept. 16, 1976 by James W. Hennessy and Bruce M. Turner, the disclosure of which is incorporated herein by reference. Further, calculated parameters which are useful in clinical diagnosis are mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC).
It is desirable to provide an apparatus in which sensed signals produced by transducer apparatus are conveniently and efficiently handled to produce output signals indicative of both measured and calculated parameters. It is also necessary that such signal be provided to utilization means so that the results may be obtain by an operator for interpretation by a pathologist. In one particularly widely used form of prior art apparatus, parameters are produced within circuitry with certain parameters values being available for viewing by an opertor on a display and with all parameter values being provided to utilization means, particularly a printer providing visible numerical indications on a print card. It is desirable to provide a system in which a technician may examine all parameters first to determine, for example, whether or not to rerun a test before engaging in the time and expense of producing a printed card.
Most importantly, it is desired to provide circuitry for registering the measured values and for producing the calculated values which is simplified in construction and efficient in operation compared to prior apparatus.